For changes appropriate to the doubling of the number of participating research groups and the acquisition of an amino acid sequencer. Its purpose is to make available a common amino acid analyzer and sequencer operation for eight research groups in the Departments of Chemistry and Biological Sciences by providing support for a research technician and the supplies and maintenance for the available equipment. The present research projects dependent on these facilities include the modification of enzyme active sites; the amino acid sequence determination of lactate dehydrogenase-X; the comparative biochemistry of oxygen-carrying proteins; the structure and function of photoreceptor subunits from phtosynthetic bacteria; proteins and proteolytic enzymes of coagulative processes; the mitochondrial membrane metabolic role of cytochrome c (E. Margoliash); the biosynthesis of bacterial cell wall components; and the structure and function of delta- aminolevulinic acid synthetase and delta-aminolevulinic acid dehydratase. These studies are supported by the Public Health Service and the continued existence of a joint amino acid analysis and sequencer operation is the most economical way of providing for their prosecution while obviating duplication of efforts and its resultant inefficiency.